"\tSome help text." is consumed by (1).
"\n" is consumed by (3).
"\t\n" is consumed by (3) again.
"config FOO" is consumed by (4), which resets first_ts to last_ts,
which does not actually change the value of first_ts.
"\tdepends on BAR\n" is consumed by (1), and does not zconf_endhelp()
as the indentation level is the same as for "\tSome help text."